1. Field of the Invention
The present invention relates to a toner conveying device to transport toner collected by a cleaning unit, or relates to an image forming apparatus using the toner conveying device.
2. Description of the Related Art
Conventionally, image forming apparatuses of electro photography using a toner include a cleaning unit to remove the toner remaining on the surface of a photosensitive drum or on the surface of an intermediate transfer member. Image forming apparatuses are known which convey the toner removed at the cleaning unit by the conveying member shoving the toner, such as a coil or a screw mounted in the toner conveying path, until the toner is discharged from the toner discharge port into the toner collecting box. Another image forming apparatus has been proposed which is configured differently, namely, the toner is conveyed in one direction by the conveying member until it is caused to fall, and fallen toner is further conveyed by another conveying member down to the toner discharge port. This configuration can give lots of freedom in selecting a position where the toner collecting box is located in the image forming apparatus.
Japanese Patent Application Laid-Open No. 2002-311712 discusses a configuration in which the toner removed by the cleaning unit is conveyed by a conveying member (first toner conveying member), and then the toner falls by its own weight into the toner conveying path. The toner that has fallen into the toner conveying path is led by another conveying member (second toner conveying member) to the toner discharge port. Moreover, Japanese Patent Application Laid-Open No. 2002-311712 proposes a configuration which has an oscillating unit arranged in the region of the toner conveying path where the toner falls by its own weight to make the oscillating unit oscillate to prevent the toner from building up and clogging the toner conveying path.
However, according to Japanese Patent Application Laid-Open No. 2002-311712, because the oscillating unit does not contact the second toner conveying member, there is an empty space between the oscillating unit and the second toner conveying member. Therefore, in this empty space, the oscillating unit is unable to break up a clumped toner.
The toner particles are likely to coagulate where they fall. Since the toner sometimes grows into large clumps at the toner fall position without being broken up by the oscillating unit, a load is added to the rotation of the second toner conveying member, often resulting in an unstable motion of the second toner conveying member.